Alkylation process



July 13, 1943;

R. B. MAsQN ALKYLATION PROCESS Filed Aug. 1, 1541 Patented July 13, 1943 UNITED STATES PATENT OFFICE ALKYLATION PROCESS Ralph Burgess Mason, Baton Rouge, La., assignor to Standard Oil Development Company, a corporation of vDelaware Application August 1,1941, serial No. 404,992

3 Claims. (Cl. 260f683.4)

'I'he present invention is concerned with refining of mineral oils. The invention is more particularly concerned with an improved alkylation process' for the production of hydrocarbon constituents boiling in the motor fuel boiling range from relatively lower boiling hydrocarbon constituents by a reaction which involves the "condensation of hydrocarbons containing a tertiary i carbon atom in the molecule with other hydrocarbon constituents. In accordance with the present process, the alkylation operation is con--l lprises a sulfuric acid having an acid concentration in the range from about 80% to about 100%, preferably from about 90% to about 100%. 'I'he reaction temperatures ,vary widely and are in the the feed is lowered to the desired degree.

refinery butane cut comprising butane, isobutane, isobutylene, alpha butylene, and beta butylene. The feed is introduced into the system by means of line l and pump 2, and passed through heat exchanging zone 3 wherein the temperature of The feed is mixed with about 5 cc. of tetraethyl lead per gallon based on fresh feed and combined with fresh catalyst comprising,90% to 987% concentrated sulfuric acid, withrecycled acid hydrocarbon emulsion, and with recycled isobutane, which latter streams are produced as hereinafter described. The fresh catalyst is introduced by means of catalyst feed line 5, the recycled isobutane by means of line 6, and the recycled acid hydrocarbon emulsion by means of line 1. For the purpose of description, it is assumed that the fresh catalyst comprises sulfuricacid of about 90% to about 'l 95% concentration; The mixture is passed by means of pump 8 through cooling zone 9 and introduced into reaction` zone 4 by suitable Jets or equivalent dispersing means I0. Turbo mixers, orifice mixers, or mechanical agitators may be employed. Cooling zone 9 prefgeneral range from about 20 F. to 100 F., and

higher. However, preferred temperatures are in the range from about F. to about 70 F. AThe time of the reaction varies considerably but in general is in the range from about 5 minutes to about 21/2 hours, or longer, depending upon operating conditions. In general', the time of contact is in the range from about 10 minutes to about 60 minutes. In operations of this character equal molecular quantities of the isoparains and olens -may be utilized. However, it has been found that it is desirable to maintain a substantial excess of a tertiary hydrocarbon in the reaction zone and to operate in a reaction medium containing `an excess of the catalyst composition.

For. example, in an operation wherein isob'utane` or isopentane is employed as the isoparafiinic reactant the mol ratio ranges from 1 to .50 and above 200 of isoparafns per mol of olens present.` I have now discovered that providing. an alkyl metalcompound be used in conjunction with the mineral acid catalyst-unexpected desirable results'are secured.

My invention may be readily understood by reference to the attached drawing illustrating one embodiment of the same. Referring specifically to the drawing, it is assumed for the purpose of illustration that the feed comprises a erably comprises a propane cooler or other equivalent means which is regulated to control the temperature of the mixture entering reaction Azone 4. Usually the temperature of' the mixture entering reaction zone 4 is in the range from about 15 Fito about 125 F., preferably at a temperature inthe range' from about 35 F. to vabout "10 F. In general, the lower the temperature of alkylation the lower will-be the acid -consumption. The reaction mixture flows upwardly through reaction zone 4 which may contain suit'- able dispersing and distributing means as, for example, pierced plates, baille plate arrangements, pack masses, or other equivalent means. Conditions are adjusted so as to secure the desired reaction time in reaction zone 4. The reaction mixture is withdrawn from reaction zone 4 by means of line Il and segregated into two streams. Qne stream is recycled to the reaction yzone by means of line 1 while the other stream is passed to initial separation zone i2 by means of line I3. The manner in which the stream withdrawn from reaction zone 4 is segregated may vary considerably. However, for the purpose of description it is assumed that approximately 2% to 25%- of the stream removed from reaction zone 4 is passed into initial separation zone I2. Temperature and pressure conditions in zone l2 are adjusted to secure the formation of a hydrocarbon phase which is removed from zone i2 by means of line I4 and an acid phase which is removed by means of line I5. A portion of the acid withdrawn from line I5 is recycled to zone 4 along with the acid hydrocarbon emulsion by means of line I6 while the remainder is Withdrawn from the system as spent alkylate withdrawn from settler I2 by means of line I4 is passed through heat exchanging zone I8 and introduced into a iinal separation zone I9 wherein any entrained acid is separated and removed by means of line 20. The hydrocarbon layer is passed into alkaline washing zone 2l by means of line 22 wherein the same is contacted with a suitable alkaline reagent which is introduced by means of line 23 and withdrawn by means of line 24. For the purpose of description it is assumed that the alkaline reagent comprises a sodium hydroxide solution. 'I'he soda washed hydrocarbon phase is withdrawn from treating zone 2| by means of line 25 and intro-A duced into an initial distillation zone 2B, which for the purpose of description is termed an isobutane tower.` Temperature and pressure conditions are adjusted in zone 26 to remove isobutane overhead by means of line 6, which stream is condensed in condensing zone 21 and recycled with the feed to reaction zone l as hereinbefore` described. 'I'he bottoms stream withdrawn from zone 28 by means of line 28 comprising normal butane and total alkylate is introduced into a .secondary distillation zone 29, which for the purpose of description is termed a normal butane tower. Temperature and pressure conditions are adjusted to remove normal butane overhead by `means of line 30, which stream is condensed in condensing zone 3I and further refined or handled as desired. In general, this stream is passed to motor fuel blending. 'I'he bottoms from secondary distillation zone 29 withdrawn by means of line 32 comprising the total alkylate is passed to a final distillation zone 33 wherein the same is fractionated to secure the desired product. Temperature and pressure conditions are adjusted in zone 33 to remove overhead by means of line 34 a hydrocarbon product having a iinal boiling point of about 290 F. to about 320 F. and an octane number in the range from' about 90 to about 95. This overhead stream is condensed in condensing zone 35 and withdrawn from the system by means of line 36. 'I'he bottoms product withdrawn by means of' line 31 comprises a fuel boiling in the range from about 320 F. to 500 F. and has an octane number in the range from about 'Z5 to about 85. This material is further refined or handled in any manner desired.

The process of my invention may be widely varied. The invention essentially comprises utilizing in conjunction with the alkylating mineral catalyst an alkyl metal compound. The alkyl metal compound of my invention which is used in commotion with the mineral acid catalyst may comprise a wide variety of substances such as alkyl metal compounds which are susceptible .to decomposition resulting in the formation of free radicals. Substances of this class are, for example, metals of group 4 of the periodic table,

such as lead, tin, and germanium, as well as zinc. However, the preferred alkyl metal compound comprises tetraethyl lead.

Although my alkyl metal compounds may be used in conjunction with any mineral acid alkylation catalyst, they are particularly desirable for use in conjunction with concentrated sulfuric acid. 'I'he amount of alkyl metal compound added will vary considerably depending upon the characteristics of the feed stock. In general, I prefer to add from about 1 to about 10 cc.s of the alkyl metal compound per gallon of tertiary hydrocarbon olen mixture. The alkyl metal compound may be directly added to the acid but in general I prefer to add the same to the feed oil.

In order to illustrate my invention further, the following example is given which should not be construed as limiting the same in any manner whatsoever:

Example approximately 5 cc.s of tetraethyl lead per gallon of isobutylene -mixture was utilized in conjunction with the sulfuric acid catalyst. The results of these operations were as follows:

Operation 1 2 Temperature F.- 15 to 40 15 to 40 Time of reaction.. ..hours 3.0 2.5 Time of feed addition do 3.0 2.0

Isobutane- Isobutylene mmm" Isobutane Feed gtgahgl isobutylene lead per gallon Wt. l'CIHg 47. 0 45. 2 Ratio: isobu aue/olelin l. l 1. 2 C|+ product:

Wt. yield on oleiins 156 121 V01. (3l-Cu 11. 6 18 Bromine No 1 1- Vol. Ca..." 3b. 4 14 Bromine N o-- 1 1. 5 Vol. Cri---- 53.0 68 Bromine No- 18 60 Octane No. of CrCx cut, A. S. T 91 l Denotes hydrocarbon constituents containing approximately designated number of carbon atoms in the molecule.

Although a relatively low isoparailin to oleilnJv ratio was utilized in the above example, it is to be understood that higher ratios may be em' ployed. In order to minimize the amount oi.' recycle of hydrocarbons required it is desirable to keep this ratio at as low a volume as is consistent with good yields of alkylate having the desired boiling range. The ratio oi' lsoparatlins to oleiins may vary in the range from about 1:1 to about 10:1. In general, it is desirable to use higher ratios than those disclosed in the example so that a higher proportion of alkylate in the C. range is obtained What I claim as new and wish to protect by Letters Patent is:

1. Process for reacting tertiary isoparailln hydrccarbons with oleiins which comprises contacting the same in the presenceof a catalyst comprising sulfuric acid and an alkyl metal compound.

2. Process as deiined by claim 1 in which said acid is a sulfuric acid havingy a concentration in the range from about 90% to about 100% and 10 in which said alkyl metal compound is tetraethyl lead.

3. Process for the production of hydrocarbon ,constitutents boiling in the motor fuel boiling range from relatively lower boiling hydrocarbons which comprises reacting tertiary isoparatlin hydrocarbons with oletins, utilizing a 90% to 100% sulfuric acid catalyst and tetraethyl lead.

RALPH comme MASON. 

